The present invention relates to a control system 10 for a motor vehicle 18, in particular for a commercial vehicle 18 with a box body 12 according to the preamble of claim 1 and a motor vehicle 18 according to the preamble of claim 5.
Currently, box bodies on commercial vehicles, such as ambulances, are essentially rigidly connected to the chassis. Accordingly, in particular in the transport of patients, only the existing suspension tuning is decisive for the well-being of patients and for physicians to work safely. Rolling and pitching movements of the vehicle in particular are perceived as very annoying by the patients and physicians.
Active suspension systems, which keep the vehicle body of a motor vehicle at the same level in all driving situations, are well known. For this purpose, in general, a controllable shock absorber (hydraulic actuator) is assigned to each wheel of the vehicle and contains, for example, a vertically adjustable hydraulic cylinder with which the spring can be more or less strongly biased by controlling the oil flow, and thus the spring force can be influenced depending on the driving situation. Such active suspension systems improve driving behavior by counteracting the movements of the vehicle, such as the vertical travel, rolling and/or pitching motions of the vehicle structure. In order to detect these movements, sensors, such as longitudinal and lateral acceleration sensors and vertical travel sensors, are usually mounted on the vehicle. As a result of the currently available capabilities in sensor detection including of the vehicle environment, known active suspension systems, which only respond based on the occurrence of an event that causes a change in vehicle dynamics, such as, for example, uneven road surfaces, are combined with a forward-looking road elevation profile recognition system in order to improve the ride comfort still further by proactive adaptation of the suspension to unevenness of the road.
Thus, for example, from U.S. Pat. No. 6,233,510 B1 a method and a system are known for predicting a road profile for use in vehicle control, for example for anti-lock braking systems and suspension systems. The road condition is determined in advance and used to influence the spring units of the vehicle. A sensor—such as a laser sensor or an image detection sensor—detects the road surface in front of the vehicle and transmits the sensor data to a control unit, which predetermines the road elevation profile lying in front of the vehicle in the direction of travel. An active suspension system with a multiplicity of spring or damper units is influenced and the spring rate, the damping rate, the pressure, the level, etc. are controlled or regulated depending on this road elevation profile.
Furthermore, a method for controlling a vehicle suspension is known from DE 10 2009 009 888 A1. The vehicle has an active suspension comprising controllable spring or damper units. Using a detection device, detection data are generated that indicate the influence of the road profile on the position and/or the movement of the vehicle structure. Furthermore, an actuation parameter is determined by a control unit depending on the detected data and forms the basis of the control of the adjustable spring or damper units of the active suspension. Moreover, the actuation parameter in the disclosed control method is also additionally dependent on a control element of a conventional active suspension control system that reacts to events that influence the vehicle dynamics.